This invention relates to a transceiver apparatus and transceiving method in a W-CDMA system. More particularly, the invention relates to a transceiver apparatus and transceiving method in a W-CDMA system for demultiplexing and decoding transmit data on a plurality of multiplexed transport channels (TrCH) using a transport format (TFI: Transport Format Indicator).
FIG. 18 is a block diagram illustrating the structure of a mobile station according to the prior art. When data is transmitted, data sent from input/output units 1a to 1n is input to a data selector 2 via internal voice codecs and video codecs, etc. The input/output units 1a to 1n are a voice input/output device and an image input/output device, etc., of a cellular telephone. In accordance with a command from a processor 3, the data selector 2 selectively inputs the transmit data, which enters via the voice or video codecs of the input/output units 1a to 1n, to transmit buffers 51 to 54 having encoding time lengths of 10, 20, 40 and 80 ms, respectively. For example, since voice code is transmitted using three transport channels (TrCH), the voice code output from voice codecs is divided into three portions and these three portions are input to the transmit buffers of the corresponding transport channels (TrCH). That is, a voice codec expresses a voice signal by {circle around (1)} an LSP parameter expressing the human vocal tract, {circle around (2)} a pitch-period component expressing the periodicity of voice, {circle around (3)} a noise component included in voice, {circle around (4)} gain of the pitch-period component and {circle around (5)} gain of the noise component, extracts each of these elements from input voice, quantizes these elements and outputs the quantized data as voice code. The LSP parameter, pitch-period component and pitch gain are important and hence are assigned to a first transport channel. The noise component and noise gain may contain a small amount of error without critical consequences and therefore are assigned to second and third transport channels.
The transmit buffers 51 to 54 write the transmit data continuously to buffer memories (not shown) every 10 ms and read out the transmit data at a stroke in burst fashion every 10 ms, 20 ms, 40 ms, 80 ms and input the read data to encoding processors 61 to 64, which constitute the succeeding stage.
The encoding processors 61 to 64 encode the transmit data of the respective lengths 10, 20, 40 and 80 ms in accordance with convolutional encoding or turbo encoding and input the encoded data to a multiplexer 7. More specifically, the encoding processor 61 outputs encoded data E10 having a duration of 10 ms, the encoding processor 62 outputs encoded data E20 having a duration of 20 ms, the encoding processor 63 outputs encoded data E40 having a duration of 40 ms, and the encoding processor 64 outputs encoded data E80 having a duration of 80 ms. For example, as shown in FIG. 19, the encoder 61 outputs encoded data 10 ms-1 every 10 ms, the encoder 62 outputs the first half 20 ms-1 and second half 20 ms-2 of the encoded data #20 in order every 10 ms, the encoder 63 outputs one-quarter portions 40 ms-1, 40 ms-2, 40 ms-3, 40 ms-4 of the encoded data E40 in order every 10 ms, and the encoder 64 outputs one-eighth portions 80 ms-1, 80 ms-2, 80 ms-3, 80 ms-4, 80 ms-5, 80 ms-6, 80 ms-7, 80 ms-8, of the encoded data E80 in order every 10 ms.
The multiplexer 7 multiplexes the encoded data that enters from the encoding processors 61–64 every 10 ms, creates one frame's worth of multiplexed data and transmits the multiplexed encoded data as in-phase component data. FIG. 19 is a diagram useful in describing the multiplexing method. In the initial tenth millisecond, encoded data {10 ms-1, 20 ms-1, 40 ms-1, 80 ms-1} is multiplexed and transmitted as a first frame. Subsequently, in 20th to 80th milliseconds, the following multiplexed data is created and transmitted as second to eighth frames:                multiplexed data: {10 ms-1, 20 ms-2, 40 ms-2, 80 ms-2} . . . second frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-3, 80 ms-3} . . . third frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-4, 80 ms-4} . . . fourth frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-1, 80 ms-5} . . . fifth frame        multiplexed data: {10 ms-1, 20 ms-2, 40 ms-2, 80 ms-6} . . . sixth frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-3, 80 ms-7} . . . seventh frame        multiplexed data: {10 ms-1, 20 ms-2, 40 ms-4, 80 ms-8} . . . eighth frameThat is, for a service whose length of encoding time is 10 ms, the data is transmitted frame by frame; for a service whose length of encoding time is 20 ms, the data is transmitted over two frames; for a service whose length of encoding time is 40 ms, the data is transmitted over four frames; and for a service whose length of encoding time is 80 ms, the data is transmitted over eight frames.        
A control signal generator 8 outputs control data such as a pilot PILO and TFCI as quadrature-component data at a fixed symbol speed. A QPSK spreader 9 subjects the input in-phase component (I-channel component) and quadrature component (Q-channel component) to spread-spectrum modulation using a predetermined spreading code, effects a digital-to-analog conversion and inputs the analog signal to a QPSK quadrature modulator 10. The latter subjects the I-channel signal and Q-channel signal to QPSK quadrature modulation, and a radio transmitter 11 frequency-converts (IF→RF) the baseband signal from the quadrature modulator 10 to a high-frequency signal, performs high-frequency amplification and transmits the amplified signal from an antenna ANTT.
FIG. 20 is a diagram useful in describing the frame format of an upstream signal from a mobile station to a base station. One frame has a length of 10 ms and is composed of 15 slots S0 to S14. User data is mapped to the I channel of QPSK modulation and control data is mapped to the Q channel of QPSK modulation. The number n of bits in each slot in the I channel for user data varies in dependence upon symbol speed. Each slot in the Q channel for control data is composed of ten bits and the symbol speed is a constant 15 kbps. The user data is formed by multiplexing the data of one or more transport channels, and the control data is composed of a TPC (Transmission Power Control) bit, TFCI (Transport Format Combination Indicator), PILOT and FBI.
FIG. 21 is a diagram useful in describing the frame format and slot arrangement of a downstream signal from a base station to a mobile station. One frame has a length of 10 ms and is composed of 15 slots S0 to S14. Each slot contains a mixture of user data Data 1, Data 2 and control data TPC, TFCI, PILOT. The data in each slot is distributed in turns to the I channel and Q channel of QPSK quadrature modulation one bit at a time, after which spread-spectrum modulation and quadrature modulation are applied, frequency conversion is carried out and the resultant signal is transmitted to the mobile station.
During reception, a radio receiver 13 subjects a high-frequency signal received from an antenna ANTR to a frequency conversion (RF→IF conversion) to obtain a baseband signal, subjects the baseband signal to quadrature detection to generate in-phase component (I component) data and quadrature component (Q component) data, applies an analog-to-digital conversion and inputs the digital data to a despreading demodulator 14. The latter applies despread processing to the I- and Q-component signals using a code identical with that of the spreading code, demodulates (synchronously detects) the transmitted encoded data and inputs the data to a demultiplexer 15. As shown in FIG. 22, the following encoded data that has been multiplexed is input to the demultiplexer 15:                multiplexed data: {10 ms-1, 20 ms-2, 40 ms-1, 80 ms-2} . . . first frame        multiplexed data: {10 ms-1, 20 ms-2, 40 ms-1, 80 ms-2} . . . second frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-3, 80 ms-3} . . . third frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-4, 80 ms-4} . . . fourth frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-1, 80 ms-5} . . . fifth frame        multiplexed data: {10 ms-1, 20 ms-2, 40 ms-2, 80 ms-6} . . . sixth frame        multiplexed data: {10 ms-1, 20 ms-1, 40 ms-3, 80 ms-7} . . . seventh frame        multiplexed data: {10 ms-1, 20 ms-2, 40 ms-4, 80 ms-8} . . . eighth frame        
The demultiplexer 15 inputs the initial 10-ms encoded data 10 ms-1 of each frame to a first decoding processor 161, inputs second 20-ms encoded data 20 ms-1, 20 ms-2 to a second decoding processor 162, inputs third 40-ms encoded data 40 ms-1, 40 ms-2, 40 ms-3, 40 ms-4 to a third decoding processor 163, and inputs fourth 80-ms encoded data 80 ms-1, 80 ms-2, 80 ms-3, 80 ms-4, 80 ms-5, 80 ms-6, 80 ms-7, 80 ms-8 to a fourth decoding processor 164. That is, data of the service for which the length of encoding time is 10 ms is received frame by frame, data of the service for which the length of encoding time is 20 ms is received over two frames, data of the service for which the length of encoding time is 40 ms is received over four frames and data of the service for which the length of encoding time is 80 ms is received over eight frames.
The first decoding processor 161, which applies error correction processing to the encoded data of length 10 ms and decodes the original transmit data, decodes the encoded data 10 ms-1 and inputs the decoded data to a succeeding receive buffer 171 every 10 ms. The second decoding processor 162, which applies error correction processing to the encoded data of length 20 ms and decodes the original transmit data, decodes the encoded data 20 ms-1, 20 ms-2 and inputs the decoded data to a succeeding receive buffer 172 every 20 ms. The third decoding processor 163, which applies error correction processing to the encoded data of length 40 ms and decodes the original transmit data, decodes the encoded data 40 ms-1 to 40 ms-4 and inputs the decoded data to a succeeding receive buffer 173 every 40 ms. The fourth decoding processor 164, which applies error correction processing to the encoded data of length 80 ms and decodes the original transmit data, decodes the encoded data 80 ms-1 to 80 ms-8 and inputs the decoded data to a succeeding receive buffer 174 every 80 ms.
The receive buffers 171, 172, 173 and 174 write the decoded data to buffer memories in a single burst every 10 ms, 20 ms, 40 ms and 80 ms, read the decoded data out of the buffer memories continuously every 10 ms and input the data to the data selector 2. In accordance with a command from the processor CPU 3, the data selector 2 selectively inputs the decoded data, which enters from each of the receive buffers 171 to 174, to the input/output units 1a to 1n. Thus, one feature of a W-CDMA system which can be mentioned is that a plurality of different services can be utilized simultaneously.
The above is a description of the overall operation of the mobile station. Multiplexing and demultiplexing will be described in greater detail below. The data transceive time intervals of the W-CDMA system are stipulated as being 10, 20, 40 and 80 ms. Such a time interval is referred to as a TTI (Transmission Time Interval) and the transceive timing is as shown in FIG. 23 on a per-TTI basis.
The channel codec transmitter (encoding processor) 6i (i=1 to 4) in this W-CDMA system accepts data transmitted from a higher layer, executes encoding processing on a per-transport-channel (TrCH) basis, multiplexes the encoded data, maps the multiplexed data to a physical channel and transmits the data. Conversely, the channel codec receiver (decoding processor) 16i (i=1 to 4) demultiplexes the data, which has been multiplexed onto the physical channel, on a per-transport-channel (TrCH) basis, executes decoding processing and delivers the results to the higher layer.
When communication starts, conditions necessary for encoding processing, such as the encoding scheme (convolutional encoding, turbo encoding, etc.), TTI and transceive format, are specified for each transport channel (TrCH) by the processor CPU 3. The transmit data is encoded in accordance with the conditions specified. If transmit data is encoded on each transport channel (TrCH), the data is multiplexed frame by frame, mapped to the physical channel and transmitted. The physical-channel data is transmitted in units of 0 ms since one frame has a duration of 10 ms. Accordingly, data having a TTI of 20 ms or greater is divided evenly into frame units of 10 ms and the data is then transmitted upon being mapped to the physical channel taking the time TTI. FIG. 24 illustrates an example in which two transport channels TrCH#1, TrCH#2 of TTIs 20 ms and 40 ms, respectively, are multiplexed and transmitted (TrCH#1=TTI 20 ms, TrCH#2=TTI 40 ms). In FIG. 24, TrCH#1-1 and TrCH#1-2 of first and second frames are the initial 20 ms of data of TrCH#1, and TrCH#1-3 and TrCH#1-4 of third and fourth frames are the next 20 ms of data of TrCH#1.
When the encoded data of each transport channel (TrCH) is multiplexed, mapped to a physical channel and transmitted, a parameter indicating how the encoded data of each transport channel TrCH has been multiplexed is created in such a manner that demultiplexing can be performed correctly on the receiving side, and this parameter is transmitted upon being attached to the physical-channel data. This parameter is referred to as a TFCI (Transmission Format Combination Indicator). The TFCI is uniquely decided by a combination of transport formats which specify the bit length per frame of data transmitted by each transport channel (TrCH).
Transport formats are numbered and each is denoted by TFI (Transport Format Indicator). An example of a TFI table is shown in FIG. 25. In the TFI table of FIG. 25, there are four types of transport formats of the transport channel TrCH#1. These are formats, for which the TFIs are 0, 1, 2 and 3, that transmit 336×0 bits, 336×1 bits, 336×2 bits and 336×3 bits per frame, respectively. Further, there are two types of transport formats of the transport channel TrCH#2. These are formats, for which the TFIs are 0 and 1, that transmit 148×0 bits and 148×1 bits per frame, respectively. If the transport channels are only of the two types TrCH#1 and TrCH#2, then the combinations of TFIs of TrCH#1 and TrCH#2 will be a total of eight and TFCIs shown in the table (TFCI table) of FIG. 26 will be assigned to these combinations.
The transport format TFIs that can be taken on by each transport channel (TrCH) are reported from the processor CPU. In FIG. 24, therefore, if 20-ms data of 336 bits×2 and 20-ms data of 336 bits×1 is transmitted from the TrCH#1 successively and 40-ms data of 148 bits×1 is transmitted from the TrCH#2, the multiplexed data (four frame's worth) mapped to a physical channel becomes the combinations of TFIs shown in FIG. 27, and the TFCIs at this time are shown in the column on the right-hand side.
If the format TFIs of each item of TrCH data mapped to the physical channel are known, as mentioned above, then it will be possible to calculate, from the TFCI table of FIG. 26, the TFCIs that indicate the combinations of TFIs. If TFCIs have been calculated, then a TFCI code word (32-bit data) is created by executing encoding processing similar to that of the user data. The TFCI code word is transmitted together with the physical-channel data.
The receiving side first decodes the TFCI code word and obtains the TFCI. The receiving side refers to the TFCI table on the basis of the TFCI obtained, detects the transport format (TFI) of each TrCH, then examines the mapping status (data length per frame) of each TrCH on the physical channel on the basis of the TFI table, demultiplexes the data on a per-TrCH basis and executes decoding processing.
The TFCI code word is obtained by converting a TFCI value to a code word constituting one row of a Hadamard matrix, by way of example. Processing for decoding the TFCI is executed by subjecting the received code to a Hadamard transform.
Processing for decoding a TFCI code word using a Hadamard transform will be illustrated below. An orthogonal code necessary to understand a Hadamard transform will be described first. When any two code words are orthogonal in Euclidean space, the two code words are referred to as orthogonal code. That is, it is said that code words u=(u1, u2, . . . , un−1, un), v=(v1, v2, . . . , vn−1, vn) are quadrature code if they satisfy the relationship indicated by the following equation:(u,v)=u1v1+u2v2+un−1vn−1unvn=0If 0s and 1s of a code word are replaced by +1 and −1, respectively, the result is referred to particularly as an analog orthogonal code. A square matrix of degree n in which code words are arrayed in each row in such a manner that the code words of any two rows will have an orthogonal relationship is referred to as a Hadamard matrix. In other words, a Hadamard matrix is a matrix in which each of the elements is +1 or −1 and any two different rows are orthogonal. An operation in which a vector of n dimensions is multiplied by this matrix is referred to as a Hadamard transform. Equation (1) below is an example of an 8-dimensional Hadamard matrix.
                    H        =                  [                                                                      +                  1                                                                              +                  1                                                                              +                  1                                                                              +                  1                                                                              +                  1                                                                              +                  1                                                                              +                  1                                                                              +                  1                                                                                                      +                  1                                                                              -                  1                                                                              +                  1                                                                              -                  1                                                                              +                  1                                                                              -                  1                                                                              +                  1                                                                              -                  1                                                                                                      +                  1                                                                              +                  1                                                                              -                  1                                                                              -                  1                                                                              +                  1                                                                              +                  1                                                                              -                  1                                                                              -                  1                                                                                                      +                  1                                                                              -                  1                                                                              -                  1                                                                              +                  1                                                                              +                  1                                                                              -                  1                                                                              -                  1                                                                              +                  1                                                                                                      +                  1                                                                              +                  1                                                                              +                  1                                                                              +                  1                                                                              -                  1                                                                              -                  1                                                                              -                  1                                                                              -                  1                                                                                                      +                  1                                                                              -                  1                                                                              +                  1                                                                              -                  1                                                                              -                  1                                                                              +                  1                                                                              -                  1                                                                              +                  1                                                                                                      +                  1                                                                              +                  1                                                                              -                  1                                                                              -                  1                                                                              -                  1                                                                              -                  1                                                                              +                  1                                                                              +                  1                                                                                                      +                  1                                                                              -                  1                                                                              -                  1                                                                              +                  1                                                                              -                  1                                                                              +                  1                                                                              +                  1                                                                              -                  1                                                              ]                                    (        1        )            
Equation (2) below is an example of a Hadamard transform.
                              H          ·          u                =                                            [                                                                                          +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                  ]                        ⁢                          (                                                                                          u                      1                                                                                                                                  u                      2                                                                                                            ·                                                                                                              u                      8                                                                                  )                                =                                                 [                                                                                          u                      1                                                                                                  +                                              u                        2                                                                                                                        +                                              u                        3                                                                                                                        +                                              u                        4                                                                                                                        +                                              u                        5                                                                                                                        +                                              u                        6                                                                                                                        +                                              u                        7                                                                                                                        +                                              u                        8                                                                                                                                                        u                      1                                                                                                  -                                              u                        2                                                                                                                        +                                              u                        3                                                                                                                        -                                              u                        4                                                                                                                        +                                              u                        5                                                                                                                        -                                              u                        6                                                                                                                        +                                              u                        7                                                                                                                        -                                              u                        8                                                                                                                                                        u                      1                                                                                                  +                                              u                        2                                                                                                                        -                                              u                        3                                                                                                                        -                                              u                        4                                                                                                                        +                                              u                        5                                                                                                                        +                                              u                        6                                                                                                                        -                                              u                        7                                                                                                                        -                                              u                        8                                                                                                                                                        u                      1                                                                                                  -                                              u                        2                                                                                                                        -                                              u                        3                                                                                                                        +                                              u                        4                                                                                                                        +                                              u                        5                                                                                                                        -                                              u                        6                                                                                                                        -                                              u                        7                                                                                                                        +                                              u                        8                                                                                                                                                        u                      1                                                                                                  +                                              u                        2                                                                                                                        +                                              u                        3                                                                                                                        +                                              u                        4                                                                                                                        -                                              u                        5                                                                                                                        -                                              u                        6                                                                                                                        -                                              u                        7                                                                                                                        -                                              u                        8                                                                                                                                                        u                      1                                                                                                  -                                              u                        2                                                                                                                        +                                              u                        3                                                                                                                        -                                              u                        4                                                                                                                        -                                              u                        5                                                                                                                        +                                              u                        6                                                                                                                        -                                              u                        7                                                                                                                        +                                              u                        8                                                                                                                                                        u                      1                                                                                                  +                                              u                        2                                                                                                                        -                                              u                        3                                                                                                                        -                                              u                        4                                                                                                                        -                                              u                        5                                                                                                                        -                                              u                        6                                                                                                                        +                                              u                        7                                                                                                                        +                                              u                        8                                                                                                                                                        u                      1                                                                                                  -                                              u                        2                                                                                                                        -                                              u                        3                                                                                                                        +                                              u                        4                                                                                                                        -                                              u                        5                                                                                                                        +                                              u                        6                                                                                                                        +                                              u                        7                                                                                                                        -                                              u                        8                                                                                                        ]                                                          (        2        )            
The way in which a Hadamard matrix is used in encoded is as described below. Here 000˜111 of transmit data is transformed to code words of first to eighth rows of the Hadamard matrix of Equation (1). Specifically, the data is transformed as follows:                Transmit data 000→(0,0,0,0,0,0,0,0) . . . first row of Hadamard matrix        Transmit data 001→(0,1,0,1,0,1,0,1) . . . second row of Hadamard matrix        Transmit data 010→(0,0,1,1,0,0,1,1) . . . third row of Hadamard matrix        Transmit data 011→(0,1,1,0,0,1,1,0) . . . fourth row of Hadamard matrix        Transmit data 100→(0,0,0,0,1,1,1,1) . . . fifth row of Hadamard matrix        Transmit data 101→(0,1,0,1,1,0,1,0) . . . sixth row of Hadamard matrix        Transmit data 110→(0,0,1,1,1,1,0,0) . . . seventh row of Hadamard matrix        Transmit data 111→(0,1,1,0,1,0,0,1) . . . eighth row of Hadamard matrix        
At the time of reception, it is necessary to discriminate transmitted orthogonal code words from received code. The operation performed is the Hadamard transform. For example, assume that R=(0,0,0,0,0,0,0,0) has been received. The following is obtained by the Hadamard transform:
                              H          ·          R                =                                            [                                                                                          +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                  ]                        ⁢                          (                                                                                          R                      1                                                                                                                                  R                      2                                                                                                            ·                                                                                                              R                      8                                                                                  )                                =                      (                                                            8                                                                              0                                                                              0                                                                              0                                                                              0                                                                              0                                                                              0                                                                              0                                                      )                                              (        3        )            Here it is determined that the code word corresponding to 8, which is the largest result of the Hadamard transform (absolute value) from among the candidates of the first to eighth rows, i.e., the code word (0,0,0,0,0,0,0,0) of the first row of the Hadamard matrix, has been sent, and the corresponding data 000 is output. It should be noted that the value of each candidate is likelihood, which indicates the degree of certainty.
The foregoing is an ideal case in which there is no transmission error. However, the transmit data can be reconstructed by the Hadamard transform even in a case where (0,0,0,0,0,0,0,0) has been received as R=(0,0,0,0,0,0,0,1), for example, owing to transmission error. Specifically, the following is obtained by the Hadamard transform:
                              H          ·          R                =                                            [                                                                                          +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                  -                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                                  +                      1                                                                                                  +                      1                                                                                                  -                      1                                                                                  ]                        ⁢                          (                                                                                          +                      1                                                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                                                  +                      1                                                                                                                                  -                      1                                                                                  )                                =                      (                                                                                +                    6                                                                                                                    +                    2                                                                                                                    +                    2                                                                                                                    -                    2                                                                                                                    +                    2                                                                                                                    -                    2                                                                                                                    -                    2                                                                                                                    +                    2                                                                        )                                              (        4        )            Since the largest absolute value (likelihood) among the candidates of the first to eighth rows is +6 of the first row, it is judged that the code word (0,0,0,0,0,0,0,0) of the first row of the Hadamard matrix has been sent, and the corresponding data 000 is output. Thus, each value of the candidate matrix following the Hadamard transform indicates the degree of certainty (likelihood). Equation (4) involves a great deal of computation. For this reason, a computation method shown in FIG. 28 has been proposed to perform the computations more efficiently. In FIG. 28, the solid lines indicate −, the dashed lines indicated + and the circles indicate adders. In accordance with this method of computation, 3×8=24 computations suffice (computations where the arrow marks cross), whereas 8×8=64 computations would be required conventionally. Computation is thus made more efficient.
The fact that a plurality of services can be sent and received upon being multiplexed can be mentioned as a feature of a W-CDMA system. Multiplexing of services is implemented by multiplex processing of transport channels (TrCHs) in the physical channel layer. In order to execute decoding processing, therefore, it is necessary to demultiplex the data of each TrCH. To achieve this, it is necessary to discriminate which transport channel (TrCH) of data has been multiplexed on a physical channel and at what ratio. Such TrCH multiplexing information can be obtained from the TFCI data (TFCI code word) received together with the user data.
When a received TFCI code word is decoded by an orthogonal transform such as the Hadamard transform, a TFCI indicating the state of TrCH multiplexing of the received user data can be detected. The transport format (TFI) of each TrCH that has been multiplexed onto the physical channel can be detected from the TFCI using the TFCI table. From this the data length used in the process of decoding each TrCH can be calculated using the TFI table.
The encoding processing applied to a TFCI is weaker than the turbo/convolutional processing applied to user data, and the probability that decoding will be erroneous is higher in comparison with user data. That is, there are instances where a correct TFCI cannot be decoded owing to transmission error or the like. If decoding of a TFCI is erroneous, correct TrCH multiplexing information will not be obtained. As a consequence, the user data cannot be demultiplexed correctly for every transport channel (TrCH), with the result that correct decoding can no longer be performed.
Thus, processing for detecting an erroneous TFCI and applying a correction is necessary. In the prior art, however, processing which corrects for an error in TFCI is not particularly executed and user data can not always be decoded correctly.